Hypoxic Exercise in Lower Extremity Artery Disease
Study Details
Study Description
Brief Summary
The aim of this randomized controlled trial is to:
Phase I: To explore, in a first pilot phase, the adequate combination of hypoxia severity and exercise intensity in patients with symptomatic lower extremity artery disease (LEAD). Acute walking performances and physiological responses (vascular and muscular) to a normobaric hypoxic exercise performed will be assessed at two different altitudes (1500 m and 2500 m).
| Condition or Disease | Intervention/Treatment | Phase |
|---|---|---|
|
N/A |
Detailed Description
The results of this first phase will then be used to determine the optimal hypoxic level for the exercise training program which will be assessed during the Phase II.
Study Design
Arms and Interventions
| Arm | Intervention/Treatment |
|---|---|
| Experimental: Exercise in hypoxia 1500m During this visit, subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 16%. |
Other: Exercise in hypoxia 1500m
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 16%. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
|
| Experimental: Exercise in hypoxia 2500m During this visit, subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 14%. |
Other: Exercise in hypoxia 2500m
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). The ambient air will be mixed with nitrogen and inspired oxygen fraction will be reduced to 14%. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
|
| Placebo Comparator: Exercise in normoxia During this visit, subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). For the exercise performed in normoxia conditions, subjects will breathe room air. |
Other: Exercise in normoxia
Subjects will perform a 6-min treadmill exercise wearing an oronasal mask connected (through a hose) with a three-way valve to an altitude simulation device (Altitrainer; SMTech, Nyon, Switzerland). For the exercise performed in normoxia conditions, subjects will breathe room air. The first 3 min will be performed at 70% of the mean speed calculated during a previous visit, and the last 3 min at an intensity between 12-14 on the Borg's scale.
|
Outcome Measures
Primary Outcome Measures
- Walking performance [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Total walking distance (in meters) during the 6 min treadmill test
- Pain free walking time [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Pain free walking time during the 6 min treadmill test
- Muscle oxygenation during exercise [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Muscle oxygenation during the 6 min treadmill test (assessed by near-infrared spectroscopy)
- Pulse wave velocity [Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Pulse wave velocity before and after the 6 min treadmill test
- Flow-mediated dilation [Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Flow-mediated dilation before and after the 6 min treadmill test
- Pulse oxygen saturation [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Pulse oxygen saturation during the 6 min treadmill test
Secondary Outcome Measures
- Ankle-brachial index [Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Ankle-brachial index before and after the 6 min treadmill test
- Toe-brachial index [Before and after each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Toe-brachial index before and after the 6 min treadmill test
- Rate of perceived exertion [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Rate of perceived exertion (RPE) will be assessed using Borg's scale. RPE is a widely used and reliable indicator to monitor and guide exercise intensity. The scale allows individuals to subjectively rate their level of exertion during 6 min treadmill test. Patients will classify their RPE between 6 (light) and 20 (maximal).
- Leg pain [After each 6 min treadmill test performed under hypoxic condition (1500 and 2500 m) and under normoxic condition (i.e., average of 3 weeks; one condition per week)]
Leg pain during exercise will be measured with a 10-points (0: "no pain" and 10: "worst imaginable pain") visual analogic scale (VAS).
Eligibility Criteria
Criteria
Inclusion Criteria:
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Patients with symptomatic LEAD (Fontaine stage ≥ IIa)
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ABI ≤ 0.9
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TBI ≤ 0.6 if incompressible arteries (diabetes and renal insufficiency)
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Signed written informed consent form
Exclusion Criteria:
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Neurological and neuromuscular disorders which can limit balance and walking
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Any history of altitude-related sickness
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Any health risks (assessed during clinical history) linked to hypoxia exposure
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Acclimatization or exposure to hypoxia of more than 2000 m for more than 48 h during a period of 6 months before the study
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Medication required for the treatment of migraines, claustrophobia that may interfere with the interpretation of the results
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Obstructive sleep apnea (> 25 Apnea-Hypopnea Index)
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Prior leg/foot amputation
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Pregnant women
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Cardiac contraindication to exercise
Contacts and Locations
Locations
| Site | City | State | Country | Postal Code | |
|---|---|---|---|---|---|
| 1 | CHUV | Lausanne | Vaud | Switzerland | 1011 |
Sponsors and Collaborators
- Centre Hospitalier Universitaire Vaudois
Investigators
- Principal Investigator: Lucia Mazzolai, Prof, Division of angiology, Lausanne University Hospital
Study Documents (Full-Text)
None provided.More Information
Publications
None provided.- 2017_00397_Phase1